Gear timing system



y 1931. E. B. TRUSLER 1,816,552

GEAR TIMING SYSTEM Filed March 11 1929 "WT Emmi farm/v05 7/17/5456 I wa/ g j I AT ORNEYS.

' keys of a predeterminedlength Ol jHLll l1 3 termined timing being v earmasmrts mm EDMUND B. T RtrsLEm or com mfisvimn,

GEAR TIMING SYSTEM Applieation filed amt 1 1, 1929. seria No. 345,907..

This invention relates to a system of lay mg a gearon itsshaft or mounting. I

The c'h'ie'l Ob e'Ct of this invention is to compensate for the wearing pf mating; teeth" and the li e s6 that theftimin'g between the 1 .14. ."vq-b/fll .H shaiits may be 1" ntalned substantially at. 1 predetermined felat lcn'.

7 he means for maintaining the' shaftsin j fedetierminea timed 'rel atio'n substantially independent of the teetli' Wear censists in "\L 51 4 1' 1" h f d- -5- -11 iovlc in lei me s a a1. gear a series o keys Of C-fi'set differences pro 'resslvely 1ncreasl ngin anu11t,: and also error-ream the unit tli'e'rebf for a purpose hereinafter to set forth. I p 7 The fun nature of the nventlen all be understood from the accompanying draw; 1ngs and the follcw'ing description and claim. a e

In the drawings,- Fig. l i's'a' side ele't "on of a pair of stan'c'lar'd' sp'u'r" gears, the sup porting shafts of which arep'arallel and parts are illustrated witllontany wear or Fig. 2 is a similar View Qfth'e same parts with the mating gears slightly we e and the angiilarj displaeemeiit from tlie predeindicatedby the angle theta (9). p

Fig; 3 is asimilar View shewing one of; the worn gears advan'c'ed'an amount equal tosubstantially that-ofi fthe Wear, sji'ch ad'- 1 Vance bein similarly indicated by the angle theta ('6) and such an'gnlar displacement being" obtained by an offset key;

F lg. 1s a similar View of a shaft laifid offset key, the offsetting beingsnhstantially twice that of the key shown in Fig. 3, the shaft having the same diameter,

Fig. 5' is a si-milar view showing'an' offset key arrangement wherein the displacement is three times that shown in Fig. 3, the shaft having the same diameter.

Fig. 6 is a similar View showing a larger key for a larger diameter shaft and gear and wherein the angular displacement is equal to that shown in Fig. 3 hut the peripheral displacement varies directly as the radii.

slct's'are in corresponding positi'ens and the backlash 01-5 wi-tli'ofit any; wear;

teeth mesh or mate with each" other'ytithout In Fig. 2, there is illust ra ed. a condition cit the same" cdnstrticti on as s'hpwn in Fig. 1, this iast amewhen theshaft carrying gear 12" isinthe 'pcsitionshown in Fig. 2; at that instant; Cree a thewear bettween the" g'earing; gear 221 is displaced by the angle thetaas indicated from the position thatthe geaehaa in ally as shown gkey does not wlearapprecia bl-yand neither (10* the's'l dtsyhut' the gearing does. If it is essential that a certain time relationship or predeeerminea positioning or predetermined rela ti'c'nishipsh-allefiist betw'een-the shafts-10 and 20' for the'silccessfnl operation of some complicated machine, then means'mu'st be" provided for maintain 'ing" such timed relatidnshipand herein,

rather than provide new gearing-,- a System of offset keyin is 'pmposed to cqrreetfor" I the departure frb'm-that relationship.-

As shown in; Fig. a-th dis lacement is eqtial t'o theangle theta (*9) whenthe initial" key is retained and when: tle gears have worn a; pe'ri her'al amount cerrespbnding to the peripheral distance chi (X). r v I In Fig. 3, the gear-has been displaced; or rathera'dyanced, sq ast compen ate for the" peripheral wearfX and when'th-is has 06- curred, the sha' ft'eeis in exact-11 11 the ame timearelatiow as' it was" Fig. I with the 10; The interconnected mechanisms; whatever they may "be; other than the gear ing, therefore; have the same time sequence operation as initially provided;

A Aisad'ditienal wear takes place',-the offset" key shown in Fig. 3 is removed and an offset key 31 is substituted therefor, which again advances the gear 22 an additional amount. Such peripheral advance'chi (X) may be an additional thousandth of an inch. A system of keys such as 30, 31 and 32 may be provided,the latter providing for three times the initial displacement taken care of I by the key 30;

In Fig. 6 an offset key construction for a large shaft diameter is illustrated. .The key is increased in size in proportion althoughv the angular displacement is the same as Fig, 3. I

The chief feature ofthe invention there fore, which will be evident from the foregoing, consists in the, successively offset key constructions shown in Figs. 3 to 6 inclusive which are adapted to substantially correct. for any shaft displacement in the'relation- .ship between two 'shaftswherein predetermined time relationship is substantially] re quired. i

In this system of keying, it will be readily the gear will be loose upon the offset key so that the invention'includes the proper-angularity of the sides of the offset key for each key as well as the progressive standard off setting. 7 V

Thefkeys preferably are standardized,-

. for example, each key can be made approxibeing shown in Figs. 3, 4 and 5.

,f mately one-quarter of the shaft diameter. That is, a two-inch shaft or shaft from one and thirteen-sixteenths inches to two'and one-eighth inches 'canuse a half inch square key and the keys can be made in sets of any predetermined number by offsetting a onethousandth of an inch, two-thousandths,

three-thousandths, etc., this arrangement Also, the gear radius divided by the shaft radius gives the-ratio between the two, and this multiplied by the offset in thousandths gives the advance at the periphery of chi for the angle-theta displacement. For example, a one inch shaft radius and four-inch gear radius would make a four, to one ratio and if the key was offset one-thousandth of an inch, the gear at the periphery would be advanced four-thousandths of an inch. Each key on the top face may have its shaft and gear diameter offset and length stamped thereon for ease and certaintyof selection.

rsiasse If the original displacement was seventhousandths offset, then seven-thousandths plus three-thousandths would make tenthousandths offset required in the new key for proper timing; Where the amount of offset is appreciable, standard key stock may be replaced by nickel key stock having greater shearing resistance. The offsetting may be in degrees instead of inches. 1

To further standardize the keying system and to make it universally applicable, there is illustrated in Fig. 7 -a shaft 40 having an exposed portion between two bearings 41 and 42. The wheel 43 or the like includes the keyway 44 that 'mates with the keyway 45 formed in shaft 40. The keys 46 as shown in-Fig. 7 are of equal length and are of a lengthat least slightly less than the distance between thehub portion of the gear 43 and the shaft bearings so that, as

shown dotted in Fig. 7, each unit length of key'46, may be individually inserted in the keyway and then driven home until the full width of key is obtained. The keys may be made in unit length, two or three times the same or any multiple thereof. This further reduces the number of keys necessary to completely stock for a keying system suffi cient to provide for substantially any keying arrangement. 7 I

The invention claimed is:

In combination with a shaft, a pair of spaced bearings,said shaft having an elon gated keyway therein extending substantially from bearingto bearing, a rotatable member having a complementary keyway and mounted upon said shaft between said bearings With predetermined longitudinal clearance, and a plurality of identical unit length keys each receivable by both keyways for keying the rotatable member to the shaft and each of a length less than said clearance permitting unlt key reception and removal i from the keyways.

In witness whereof, I have hereunto affixed my signature. 

